After a computer has been switched on, the computer starts a boot process (hereinafter, referred to as “the boot”) for reading a predetermined program (hereinafter, referred to as “the boot file”) from a boot disk to a main memory. This enables a user to run application programs (hereinafter, referred to as “the applications”) for operation after a series of boot files are loaded. At the time of starting to use the computer, the boot processing is completed in a short time because the size of the boot files is relatively small. However, after the computer has been used for many years, the user might have installed various programs therein. These programs have been incorporated into the boot files and run automatically without the user's knowledge. As a result, the boot time is increased.
Patent Document 1 describes prefetching for reducing the start time by omitting wasteful page faults and seeks. The prefetching is a function of checking the access status of the files to a hard disk drive (HDD) by tracing the behavior of the program being booted during the last boot and earlier boots and then reading a predetermined file ahead into a cache area of the main memory during the next boot and subsequent boots on the basis of the result. An access log is recorded for each file and stored in a predetermined directory.
Each file includes records of data of access patterns to the HDD for each program. During booting, the files are read ahead into the main memory on the basis of the access log. The recent operating systems (OS) of Windows® further has a function called SuperFetch, derived by developing the prefetching disclosed in Patent Document 1. The SuperFetch function helps manage a problem introduced by virus scans and disk optimizations. Normally, during a period of time when the user is not operating the computer, an application's memory page will be swapped out from a cache area after a virus scan and disk optimization is performed. The SuperFetch function copes with this problem by swapping-in the swapped-out memory page after the completion of the virus scan and disk optimization.
Patent Document 2 discloses a technique for reducing the boot time. The technique was invented by the inventor of the present invention and assigned to the applicant of the present invention. In the invention described in Patent Document 2, processes of a boot file that do not affect the operation of a computer, even in the case of being run on-demand, are suspended temporarily during booting and then resumed on-demand after a completion of the boot. As a result, this enables a reduction in the number of boot files automatically executed after being loaded, which reduces the boot time while preventing problems such as boot delay and stagnation.
Patent Document 3 discloses a virtual storage management system in a working-set method. The virtual storage management system dynamically sets a cache memory space in the main memory by using an unused page of another working set. Further, Patent Document 4 discloses a technique in which a user sets or changes the priority of paging-out a memory page to control working sets in units of a job. Finally, Non-patent Document 1 describes a method of managing a working set in Windows®.
Patent Document 1—U.S. Pat. No. 6,633,968
Patent Document 2—Japanese Patent Application Laid-Open No. 2011-103093
Patent Document 3—Japanese Patent Application Laid-Open No. Hei 5-20201
Patent Document 4—Japanese Patent Application Laid-Open No. Hei 10-31624
Non-patent Document 1—Inside Microsoft Windows®, Fourth Edition, vol. 1, Microsoft official practical guide, Nikkei BP Soft Press